An engine mounted on a vehicle or the like is provided with a valve operating system, auxiliary devices, a hydraulic controller and so on. For operation, lubrication and control, oil discharged from an oil pump is fed to such valve operating system, auxiliary devices and hydraulic controller. The hydraulic controller in the engine supplies the oil discharged from the oil pump to a hydraulic-actuated device through a hydraulic control valve to actuate the hydraulic-actuated device.
As such a hydraulic control valve mounting structure in an engine, the one shown in FIG. 10 is known. In FIG. 10, the reference numeral 202 denotes an engine, 204 a cylinder block, 206 a cylinder head, 208 a head cover, 210 an oil pan, 212 a crank shaft, and 214 a chain cover. The engine 202 is provided with a hydraulic controller, a variable valve timing device 216 which changes the valve timing of intake and exhaust valves.
The variable valve timing device 216 comprises a hydraulic actuator 218 serving as a hydraulic-actuated device mounted on one end side of a cam shaft (not shown) and an oil control valve 220 serving as a hydraulic control valve which is secured to an outer surface 222 of the cylinder head 206 and which supplies the hydraulic actuator 218 with oil discharged from an oil pump (not shown).
In the variable valve timing device 216, the operation of the oil control valve 220 is controlled in accordance with the state of operation of the engine 202 by a control means (not shown), the oil discharged from an oil pump (not shown) is fed to the hydraulic actuator 218 after division into oil for advance and oil for retard by the oil control valve 220, and the phase of the cam shaft relative to the crank shaft 212 is changed to change the valve timing of the intake and exhaust valves.
This type of hydraulic control valve mounting structure in an engine is disclosed in Japanese Patent Laid Open Nos. 100611/96, 184331/98, 317412/97 and 71315/93.
In the hydraulic control valve mounting structure disclosed in Japanese Patent Laid Open No. 100611/96, a cam phase angle changing device is used as a hydraulic controller, and a hydraulic control solenoid valve in the cam phase angle changing device is mounted to a front cover which covers the front sides of the cylinder block and crank case.
In the hydraulic control valve mounting structure disclosed in Japanese Patent Laid Open No. 184331/98, a valve timing changing device is used as a hydraulic controller, and an oil control valve in the valve timing changing device is mounted to a cam cap which supports a cam shaft.
In the hydraulic control valve mounting structure disclosed in Japanese Patent Laid Open No. 317412/97, a valve timing changing mechanism is used as a hydraulic controller, and a hydraulic control valve in the valve timing changing mechanism is mounted to a cam cap which supports a cam shaft.
In the hydraulic control valve mounting structure disclosed in Japanese Patent Laid Open No. 71315/93, a variable valve timing mechanism is used as a hydraulic controller, and a hydraulic control valve in the variable valve timing mechanism is mounted between V banks of a V-shaped internal combustion engine.
In the conventional structure shown in FIG. 10 for mounting the oil control valve 220 serving as a hydraulic control valve in the engine 202, since the oil control valve 220 is attached to the outer surface 222 of the cylinder head 206, there is a fear that the oil control valve 220 may come into contact with a vehicle body (not shown) at the time of mounting or removing the engine 202 to or from the vehicle body. Thus, in the conventional mounting structure it is likely that the oil control valve 220 will be damaged by contact thereof with the vehicle body and that the function of the variable valve timing device 216 serving as a hydraulic controller will be impaired.
In order to eliminate or minimize the above-mentioned inconvenience, in a hydraulic control valve mounting structure in an engine wherein a chain cover is attached to both a cylinder block and a cylinder head so as to cover a timing chain which transmits the rotation of a crank shaft of the engine to both intake and exhaust cam shafts, an oil pump driven by the crank shaft is provided, and a hydraulic control valve which supplies oil discharged from the oil pump to a hydraulic-actuated device in a hydraulic controller is attached to the chain cover, the present invention is characterized in that the hydraulic control valve is attached to an outer surface of the chain cover while being positioned so that an upper portion thereof is covered at least partially with a mount installing boss portion of the chain cover and is covered at least partially with a water pipe secured to a pipe mounting boss portion of the chain cover.
The present invention is further characterized in that the hydraulic control valve is attached to the outer surface of the chain cover while being positioned so that a lower portion thereof is surrounded and covered with a crank pulley on the crank shaft and a plurality of auxiliary devices' pulleys which are driven by the crank shaft.
In the hydraulic control valve mounting structure of the present invention, since a hydraulic control valve is attached to an outer surface of a chain cover while being positioned so that an upper portion thereof is covered at least partially with a mount installing boss portion of the chain cover, the hydraulic control valve can be prevented from coming into contact with a vehicle body by means of the mount installing boss portion at the time of installing the engine on the vehicle body; besides, since the hydraulic control valve is attached to the outer surface of the chain cover while being positioned so that the upper portion thereof is at least partially covered with a water pipe secured to a pipe mounting boss portion, the hydraulic control valve can be prevented from coming into contact with the vehicle body by the water pipe at the time of installing the engine on the vehicle body. Further, since the hydraulic control valve is attached to the outer surface of the chain cover while being positioned so that a lower portion thereof is surrounded and covered with both a crank pulley and a plurality of auxiliary devices' pulleys, the hydraulic control valve can be prevented from coming into contact with the vehicle body by the auxiliary devices' pulleys at the time of removing the engine from the vehicle body.